Riyad as-Salihin, Book 1, Hadith 359 (In-Book) ⓘ
Anas bin Malik (May Allah be pleased with him) reported: Messenger of Allah said, "If a young man honours an older person on account of his age, Allah appoints someone to show reverence to him in his old age"[At-Tirmidhi].
وعن أنس رضي الله عنه قال: قال رسول الله صلى الله عليه وسلم : "ما أكرم شاب شيخًا لسنه إلى قيض الله له من يكرمه عند سنه" ((رواه الترمذي وقال: حديث غريب)).